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Hybrid bubble chamber studies of K+ p and K- p interactions at 75-GeV/c

Description: We propose to expose the FNAL 30' liquid hydrogen bubble chamber to K{sup +} and K{sup -} beams both at 75 GeV/c. Each exposure consists of 100,000 equivalent K pictures. We plan to use the upstream tagging system currently in place and a downstream spectrometer with acceptance considerably increased over that of the current PHC system. This new downstream system will also be equipped with a lead glass photon detector with good spatial and energy resolution. We will study comparison of K{sup +} and K{sup -} results, as well as results from {pi}{sup +}, {pi}{sup -} , and {bar p} beams at this energy which are the subject of separate proposals.
Date: January 1, 1975
Creator: Bugg, W.M.; Condo, G.T.; Hart, E.L.; Handler, T.; U., /Tennessee; Cohn, H.O. et al.
Partner: UNT Libraries Government Documents Department

A Cone Jet-Finding Algorithm for Heavy-Ion Collisions at LHCEnergies

Description: Standard jet finding techniques used in elementary particle collisions have not been successful in the high track density of heavy-ion collisions. This paper describes a modified cone-type jet finding algorithm developed for the complex environment of heavy-ion collisions. The primary modification to the algorithm is the evaluation and subtraction of the large background energy, arising from uncorrelated soft hadrons, in each collision. A detailed analysis of the background energy and its event-by-event fluctuations has been performed on simulated data, and a method developed to estimate the background energy inside the jet cone from the measured energy outside the cone on an event-by-event basis. The algorithm has been tested using Monte-Carlo simulations of Pb+Pb collisions at {radical}s = 5.5 TeV for the ALICE detector at the LHC. The algorithm can reconstruct jets with a transverse energy of 50 GeV and above with an energy resolution of {approx} 30%.
Date: July 27, 2006
Creator: Blyth, S.-L.; Horner, M.J.; Awes, T.C.; Cormier, T.; Gray, H.M.; Klay, J.L. et al.
Partner: UNT Libraries Government Documents Department

Evaluation of radioactive background rejection in 76Ge neutrino-lessdouble-beta decay experiments using a highly segmented HPGe detector

Description: A highly segmented coaxial HPGe detector was operated in a low background counting facility for over 1 year to experimentally evaluate possible segmentation strategies for the proposed Majorana neutrino-less double-beta decay experiment. Segmentation schemes were evaluated on their ability to reject multi-segment events while retaining single-segment events. To quantify a segmentation scheme's acceptance efficiency the percentage of peak area due to single segment events was calculated for peaks located in the energy region 911-2614 keV. Single interaction site events were represented by the double-escape peak from the 2614 keV decay in {sup 208}Tl located at 1592 keV. In spite of its prototypical nature, the detector performed well under realistic operating conditions and required only minimal human interaction. Though the energy resolution for events with interactions in multiple segments was impacted by inter-segment cross-talk, the implementation of a cross-talk correlation matrix restored acceptable resolution. Additionally, simulations utilizing the MaGe simulation package were performed and found to be in good agreement with experimental observations verifying the external nature of the background radiation.
Date: February 5, 2007
Creator: Chan, Yuen-Dat; Campbell, D.B.; Vetter, K.; Henning, R.; Lesko, K.; Chan, Y.D. et al.
Partner: UNT Libraries Government Documents Department

A search for anisotropy in the arrival directions of ultra high energy cosmic rays recorded at the Pierre Auger Observatory

Description: Observations of cosmic ray arrival directions made with the Pierre Auger Observatory have previously provided evidence of anisotropy at the 99% CL using the correlation of ultra high energy cosmic rays (UHECRs) with objects drawn from the Veron-Cetty Veron catalog. In this paper we report on the use of three catalog independent methods to search for anisotropy. The 2pt-L, 2pt+ and 3pt methods, each giving a different measure of self-clustering in arrival directions, were tested on mock cosmic ray data sets to study the impacts of sample size and magnetic smearing on their results, accounting for both angular and energy resolutions. If the sources of UHECRs follow the same large scale structure as ordinary galaxies in the local Universe and if UHECRs are deflected no more than a few degrees, a study of mock maps suggests that these three methods can efficiently respond to the resulting anisotropy with a P-value = 1.0% or smaller with data sets as few as 100 events. Using data taken from January 1, 2004 to July 31, 2010 we examined the 20, 30, ..., 110 highest energy events with a corresponding minimum energy threshold of about 51 EeV. The minimum P-values found were 13.5% using the 2pt-L method, 1.0% using the 2pt+ method and 1.1% using the 3pt method for the highest 100 energy events. In view of the multiple (correlated) scans performed on the data set, these catalog-independent methods do not yield strong evidence of anisotropy in the highest energy cosmic rays.
Date: January 1, 2012
Creator: Abreu, P.
Partner: UNT Libraries Government Documents Department

Calorimeter Simulation with Hadrons in CMS

Description: CMS is using Geant4 to simulate the detector setup for the forthcoming data from the LHC. Validation of physics processes inside Geant4 is a major concern in view of getting a proper description of jets and missing energy for signal and background events. This is done by carrying out an extensive studies with test beam using the prototypes or real detector modules of the CMS calorimeter. These data are matched with Geant4 predictions using the same framework that is used for the entire CMS detector. Tuning of the Geant4 models is carried out and steps to be used in reproducing detector signals are defined in view of measurements of energy response, energy resolution, transverse and longitudinal shower profiles for a variety of hadron beams over a broad energy spectrum between 2 to 300 GeV/c. The tuned Monte Carlo predictions match many of these measurements within systematic uncertainties.
Date: November 1, 2008
Creator: Piperov, Stefan & /Sofiya, Inst. Nucl. Res. /Fermilab
Partner: UNT Libraries Government Documents Department

PERFORMANCE-LIMITING DEFECTS IN CDZNTE DETECTORS.

Description: We studied the effects of small, <20 {micro}m, Te inclusions on the energy resolution of CdZnTe gamma-ray detectors using a highly collimated X-ray beam and gamma-rays, and modeled them via a simplified geometrical approach. Previous reports demonstrated that Te inclusions of about a few microns in diameter degraded the charge-transport properties and uniformity of CdZnTe detectors. The goal of this work was to understand the extent to which randomly distributed Te-rich inclusions affect the energy resolution of CZT detectors, and to define new steps to overcome their deleterious effects. We used a phenomenological model, which depends on several adjustable parameters, to reproduce the experimentally measured effects of inclusions on energy resolution. We also were able to hound the materials-related problem and predict the enhancement in performance expected by reducing the size and number of Te inclusions within the crystals.
Date: October 29, 2006
Creator: BOLOTNIKOV, A.E.; CAMARDA, G.S.; CUI, Y.; KOHMAN, K.T.; LI, L.; SALOMON, M.B. et al.
Partner: UNT Libraries Government Documents Department

Performance of the radphi detector and trigger in a high rate tagged photon beam

Description: We describe the design and operation of a detector system for measuring all-photon decays of mesons photoproduced in a tagged photon beam with energies between 4.3 and 5.4 GeV and a flux of 5×107 tagged photons per second. Photons from meson decays were detected with a lead-glass calorimeter with an energy resolution of 11% at 1 GeV. Various veto and trigger components were also present. Final states with as many as six photons were successfully detected and reconstructed.
Date: January 1, 2007
Creator: Jones, R.T.; Bogue, T.; Evans, B.E.; Kornicer, M.; Dzierba, A.R.; Gardner, R. et al.
Partner: UNT Libraries Government Documents Department

Semiconductor Radiation Detectors with Frisch Collars and Collimators for Gamma Ray Spectroscopy and Imaging

Description: To study CdZnTe as a high energy resolution gamma ray detector with a novel new design, and to build a detector array from the new detector design
Date: December 4, 2006
Creator: McGregor, Douglas; Kargar, Alireza; Harrison, Mark; Brooks, Adam; McNei, Walter; Lowell, Rans et al.
Partner: UNT Libraries Government Documents Department

Temperature Study of CdZnTe Coplanar-Grid Detectors

Description: The coplanar-grid (CPG) and other electron only detection techniques have made possible the use of CdZnTe-based detectors for gamma-ray spectroscopy when high efficiency, good energy resolution, and near room temperature operation are required. Despite the demonstrated potential of the technologies, widespread use remains hampered in part by the limited availability of the highly uniform CdZnTe material required for high-resolution spectroscopy. However, it has been recently shown that mild cooling of CdZnTe CPG detectors can result in a significant improvement in the energy resolution of the detectors thereby allowing a wider range of material to be used for high-resolution applications. In this paper, we show that improved spectroscopic performance can consistently be achieved through a combination of detector cooling and increased detector bias. Energy resolutions of about 1 % FWHM at 662 keV for detector volumes up to 2.3 cm{sup 3} have been obtained at -20 C. With the electronic noise subtracted, this amounts to an intrinsic resolution of 0.76 %. We also show that further cooling of the detectors to -30 C leads to field polarization and a loss of spectroscopic performance.
Date: February 14, 2006
Creator: Amman, Mark; Lee, Julie S. & Luke, Paul N.
Partner: UNT Libraries Government Documents Department

Efficiency of TTAC's ORTEC IDM

Description: ORNL's Technical Testing and Analysis Center (TTAC) acquired a High Purity Germanium Detector (HPGe) from ORTEC - a variant called an Interchangeable Detection Module (IDM). This detector has excellent energy resolution as well as high intrinsic efficiency. The purpose of this report is to detail the determination of the efficiency curve of the IDM, so future measurements can quantify the (otherwise unknown) activity of sources. Without such a curve, the activity cannot be directly reported by use of the IDM alone - a separate device such as an ion chamber would be required. This builds upon the capability of TTAC. The method for determining the energy-dependent intrinsic efficiency is laid-out in this report. It's noteworthy that this basic technique can be applied to any spectroscopic radiation detector, independent of the specific type (e.g. NaI, CzT, ClYC).
Date: August 1, 2012
Creator: Livesay, Jake; Combs, Jason C; Margrave, Timothy E & Miller, Ian J
Partner: UNT Libraries Government Documents Department

Study of New Muon Energy Detector at Tevatron Muon Beam Line

Description: A new method for the energy determination of Tev muons will be studied at Tevatron beam line. More than 200 layers scintillation shower detector is located in front of Tevatron muon experimental group (E-665). The energy resolution of small shower detector induced by muons will be experimentally obtained.
Date: January 1, 1986
Creator: Mitsui, K.; Muraki, Y.; Okada, A.; Ohashi, Y.; U., /Tokyo; Matsumoto, S. et al.
Partner: UNT Libraries Government Documents Department

BPM System Improvements

Description: During the accelerator studies period of 12/90 through 1/91 the Accumulator BPM system was investigated in some detail in an effort to improve its reliability and accuracy in making closed orbit measurements. The motivation for this is to try and improve the beam energy resolution for E760. The relativistic {beta} of the {bar p} is given by {beta} = f{sub R}L/c where f{sub R} is the revolution frequency, L is the orbit length ({approx} 474050mm), and c is the speed of light. Hence, the error in {beta} is given by d{beta}/{beta} = df{sub R}/f{sub R} + dL/L. Since df{sub R}/f{sub R} is {approx} 2 x 10{sup -7}, the main contribution to the error comes from dL. During the E760 run of 5/90 to 9/90 dL was estimated to be {approx} 1mm. It is thought that this can be reduced to {approx} .25mm with proper use of the present BPM system. L is given by L = L{sub 0} + {delta}L where L{sub 0} is the accurately known orbit length of a reference orbit (extracted from an energy scan of the J/{Psi} or {Psi}{prime}), and {delta}L is the difference orbit between the current orbit and the reference orbit. SL is calculated in the 1st approximation by {delta}L = {Sigma}{sub i}C{sub i}{Sigma}{sub j}{Delta}BPM{sub ij} where {Delta}BPM{sub ij} is the horizontal difference orbit at the ith BPM in the jth sector and C{sub i} are constants depending upon the location of the BPM pickup and the strength of the quadrupoles. Table I lists the constants C{sub i}, and Fig. 1 shows a typical difference orbit, {Delta}BPM{sub ij}. These studies were all done with 'reverse protons' and concentrated on closed orbit measurements with the Accumulator horizontal BPMs. The low frequency (H=2) mode of the BPM system is used in all cases, therefore it is ...
Date: April 24, 1991
Creator: Church, M.
Partner: UNT Libraries Government Documents Department

Muon g-2 Calorimeter Prototypes

Description: The proposed design is a tungsten-scintillating fiber calorimeter with 35 segments, each read out by a separate PMT. Tungsten, which is significantly denser than lead, produces compact showers. This is necessary, in order to improve shower separation in analysis and to fully contain the showers within a calorimeter that satisfies the strict space constraints of the experiment. A single calorimeter segment (4 x 6 x 15 cm{sup 3}) has been constructed in order establish the feasibility of the new design and study its properties. Initial tests of the detector segment at the Paul Scherrer Institute were conducted with a low energy < 400 MeV/c electron beam. A higher-energy test with electrons up to a few GeV/c was performed at the Test Beam Facility under the experimental number T-967. All data from that test have been analyzed and published, and the tungsten-scintillating fiber calorimeter still appears to be a viable candidate. For this test beam run, a larger calorimeter (15 x 15 x 11 cm{sup 3}) has been constructed and an emphasis will be placed on understanding shower leakage and the ability to separate pileup events with a more granular readout. The experimenters will measure the energy resolution, linearity, and shower size of the calorimeter segment. This will provide important information for finalizing decisions on the angle of the fibers relative to the incoming electrons and the optimal granularity of the readout.
Date: May 3, 2010
Creator: Polly, Chris
Partner: UNT Libraries Government Documents Department

Accelerator R&D toward Muon Collider and Neutrino Factory

Description: Over the last decade there has been significant progress in developing the concepts and technologies needed to produce, capture, accelerate and collide high intensity beams of muons. At present, a high-luminosity multi-TeV muon collider presents a viable option for the next generation lepton-lepton collider, which is believed to be needed to fully explore high energy physics in the era following LHC discoveries. Such a collider can offer superb energy resolution, smaller size, and potentially cost and power consumption compared to multi-TeV e{sup +}e{sup -} linear colliders. This article briefly reviews the motivation, design and status of accelerator R&D for Muon Collider and Neutrino Factory.
Date: October 1, 2009
Creator: Shiltsev, Vladimir
Partner: UNT Libraries Government Documents Department

Evaluation of production samples of the scintillators LaBr3:Ce and LaCl3:Ce

Description: We report on the evaluation of the performance of two recently developed scintillator materials, LaCl{sub 3}:Ce and LaBr{sub 3}:Ce, at the task of gamma ray spectroscopy. Their performance is compared to a standard scintillator used for gamma ray spectroscopy--a 25 mm diameter 25 mm tall cylinder of NaI:Tl. We measure the pulse height, energy resolution, and full-energy efficiency of production LaBr{sub 3}:Ce and LaCl{sub 3}:Ce scintillation crystals of different sizes and geometries for a variety of gamma-ray energies. Using production rather than specially selected crystals will establish whether immediate large-scale use is feasible. The crystal is excited by gamma rays from one of six isotopic sources ({sup 125}I, {sup 241}Am, {sup 57}Co, {sup 22}Na, {sup 137}Cs, and {sup 60}Co) placed 15 cm away from the scintillator. Our measurements show that both LaCl{sub 3} and LaBr{sub 3} outperform NaI:Tl in almost all cases. They outperform NaI:Tl at all energies for the photopeak fraction and counting rate measurements, and for energy resolution at higher energies (above 200 keV for LaCl{sub 3} and 75 keV for LaBr{sub 3}). The performance of production crystals is excellent and these scintillators should be considered for immediate use in systems where stopping power and energy resolution are crucial.
Date: September 15, 2005
Creator: Choong, Woon-Seng; Derenzo, Stephen E. & Moses, William W.
Partner: UNT Libraries Government Documents Department

A field-deployable gamma-ray spectrometer utilizing high pressure xenon

Description: Most nuclear materials in the nuclear energy, safeguards, arms control, and nonproliferation regimes emit gamma rays with a unique signature. Currently, two categories of spectrometers are available to evaluate these materials: (1) Semiconductors, with excellent energy resolution, which operate at cryogenic temperatures. (2) Scintillation detectors, which function at ambient temperature, but with poor energy resolution. A detector which functions for extended periods in a range of environments, with an energy resolution superior to that of a scintillation spectrometer, would have evident utility. Recently, in the research community, such a device has evolved, an ionization chamber utilizing xenon gas at very high pressure (60 atm). Its energy resolution, typically, is 20 keV for the 661 keV gamma ray of {sup 137}Cs. With high xenon density and its high atomic number (Z=54), and superior energy resolution, its sensitivity is comparable to that of a scintillator.
Date: May 1, 1997
Creator: Smith, G.C.; Mahler, G.J.; Yu, Bo; Kane, W.R. & Lemley, J.R.
Partner: UNT Libraries Government Documents Department

Uniformity requirements in CMS hadron calorimetry

Description: Practical considerations of calorimeter systems require a specification of the allowed manufacturing tolerances. The tightness of these requirements directly makes an impact on the assembly costs of the calorimeter. For that reason, a precise and well defined set of criteria is mandatory. In addition, the intrinsic limitations of hadron calorimetry define the level of accuracy needed in the manufacture of such devices. Therefore, considerations of the limitations on energy measurement accuracy due to Physics should define the needed level of effort to produce a uniform calorimetric device.
Date: February 1, 1996
Creator: Green, D.
Partner: UNT Libraries Government Documents Department

Predicted performance of neutron spectrometers using scintillating fibers

Description: A variety of needs exists for knowing the energy spectral content of a neutron flux. Among these needs are arms-control and national-security applications, which arise because different neutron sources produce different neutron energy spectra. This work is primarily directed at these applications. The concept described herein is a spectrometer in the same sense as a Bonner sphere. The instrument response reflects a statistical average of the energy spectrum. The Bonner sphere is an early rendition of this class. In this, a neutron detector is placed at the center of a moderating (and absorbing) sphere (of varying thickness and composition). Spectral unfolding is required, and the resolution and efficiency are, typically, poor, although the potential bandwidth is very large. A recent variation on the Bonner-sphere approach uses {sup 3}He gas proportional counters with resistive wires to locate the position of the event (Toyokawa et al 1996). The spectrometer concept investigated here has the potential for better resolution and much improved neutron efficiency compared to Bonner spheres and similar devices. These improvements are possible because of the development of neutron-sensitive, scintillating-glass fibers. These fibers can be precisely located in space, which allows a corresponding precision in energy resolution. Also, they can be fabricated into arrays that intercept a large fraction of incident thermal neutrons, providing the improvement in neutron economy.
Date: February 14, 2000
Creator: Craig, RA & Bliss, M
Partner: UNT Libraries Government Documents Department

Design of a high-resolution high-stability positioning mechanism for crystal optics

Description: The authors present a novel miniature multi-axis driving structure that will allow positioning of two crystals with better than 50-nrad angular resolution and nanometer linear driving sensitivity.The precision and stability of this structure allow the user to align or adjust an assembly of crystals to achieve the same performance as does a single channel-cut crystal, so they call it an artificial channel-cut crystal. In this paper, the particular designs and specifications, as well as the test results,for a two-axis driving structure for a high-energy-resolution artificial channel-cut crystal monochromator are presented
Date: October 11, 1999
Creator: Shu, D.; Toellner, T. S. & Alp, E. E.
Partner: UNT Libraries Government Documents Department

High power laser for peening of metals enabling production technology

Description: Cryogenic energy-dispersive x-ray detectors are being developed because of their superior energy resolution ((less than or equal to) 10 eV FWHM for keV x rays) compared to semiconductor EDS systems. So far, their range of application is limited due to their comparably small size and low count rate. We present data on the development of superconducting tunnel junction (STJ) detector arrays to address both of these issues. A single STJ detector has a resolution around 10 eV below 1 keV and can be operated at count rates of order 10,000 counts/s. We show that the simultaneous operation of several STJ detectors does not diminish their energy resolution significantly, while increasing the detector area and the maximum count rate by a factor given by the total number of independent channels.
Date: June 18, 1998
Creator: Daly, J.; Dane, C.B.; Hackel, L.A. & Harrison, J.
Partner: UNT Libraries Government Documents Department

Superconducting tunnel junction array development for high-resolution energy-dispersive x-ray spectroscopy

Description: Cryogenic energy-dispersive x-ray detectors are being developed because of their superior energy resolution ((less than or equal to) 10 eV FWHM for keV x rays) compared to semiconductor EDS systems. So far, their range of application is limited due to their comparably small size and low count rate. We present data on the development of superconducting tunnel junction (STJ) detector arrays to address both of these issues. A single STJ detector has a resolution around 10 eV below 1 keV and can be operated at count rates of order 10,000 counts/s. We show that the simultaneous operation of several STJ detectors does not diminish their energy resolution significantly, while increasing the detector area and the maximum count rate by a factor given by the total number of independent channels.
Date: July 1, 1998
Creator: Barfknecht, A. T.; Cramer, S. P; Frank, M.; Friedrich, S.; Hiller, L. J.; Labov, S. E. et al.
Partner: UNT Libraries Government Documents Department

Ultra-high resolution spectroscopy of the He doubly excited states

Description: Photoionization spectra of the doubly-excited states of He were measured using beamline 9.0.1 at the Advanced Light Source. The beamline utilizes a 4.5 m long 8 cm period undulator as its source together with a spherical grating monochromator to provide an extremely bright source of photons in the range of 20 {minus} 300 eV. A resolving power (E/{Delta}E) of 64,000 was obtained from the 1 MeV FWEM (2p,3d) doubly excited state resonance of He at 64.12 eV. The high brightness of the source and the very high quality optical elements of the beamline were all essential for achieving such a high resolution. The beamline components and operation are described and spectra of the double excitation resonances of He presented.
Date: November 1, 1995
Creator: Bozek, J. D.; Schlachter, A. S.; Kaindl, G. & Schulz, K.
Partner: UNT Libraries Government Documents Department

INEL1-microvolt spectrometer-reference instrument WBS 1.7.8.

Description: INEL1 is a near-backscattering crystal-analyzer spectrometer designed to provide energy resolution of 5 to 15 {micro}eV. Figure 1 provides a schematic representation of INEL1, and Table 1 gives the parameters for this instrument. Two different analyzer crystal arrays allow two different primary choices of scattered neutron energy, and the possibility of using different orders from these arrays provides even more scattered energy choices.
Date: January 18, 1999
Creator: Crawford, R. K.
Partner: UNT Libraries Government Documents Department